Nano fiber composite sheet and method of manufacturing the same

ABSTRACT

There is provided a method of manufacturing a nanofiber composite sheet, the method including preparing a base sheet, surface-treating the base sheet, and forming a substrate layer having a nanofiber structure on the surface-treated base sheet.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the priority of Korean Patent Application No. 10-2013-0076032 filed on Jun. 28, 2013, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a nanofiber composite sheet having permeability and excellent adhesion between a nanofiber substrate layer and a base sheet, and a method of manufacturing the same.

2. Description of the Related Art

Nanofibers have a small diameter and relatively large surface area versus volume as compared to existing fibers.

The small diameter of the nanofiber has advantages in that a soft-touch fiber, that is, a soft touch feel of a fabric, may be implemented and appropriate physical properties in various usages due to a relatively high specific surface area as compared to weight, high porosity, and the like may be implemented. Therefore, it is expected that technology using nanofibers as a material will be developed as a novel technology for improving limitations on the performance of existing universal fiber materials and will be utilized in materials having a separating function, medical materials, artificial blood vessels, nanocomposite materials, and the like, and will be capable of being widely utilized throughout industrial fields such as in the information technology (IT) field, the energy production field, as well as in biomedical fields.

When nanofibers are utilized in various industrial fields, a combination of nanofibers and a different kind of material may sometimes be demanded in order to supplement the physical properties of the nanofibers themselves or to significantly increase the original properties thereof. In general, in the combination of the nanofiber and the different kind of material, a method of forming an adhesive layer by applying an adhesive resin or spraying a spray material, a method of using an adhesive film, or the like, may be used.

However, in the case of using an adhesive agent, a component of the adhesive agent may affect properties of a main material or may allow target properties to be deteriorated, resulting in a deterioration of the quality of a completed product, such that a differentiated method of solving the problems as described above has been increasingly demanded.

The following Related Art Document merely discloses a method of performing a plasma treatment on nanofibers, but fails to disclose a method of performing a surface-treatment on a base sheet as described in the present invention, thereby having a difference from the present invention.

[Related Art Document]

Korean Patent No. KR 10-0792894

SUMMARY OF THE INVENTION

An aspect of the present invention provides a nanofiber composite sheet having permeability and excellent adhesion between a nanofiber substrate layer and a base sheet, and a method of manufacturing the same.

According to an aspect of the present invention, there is provided a method of manufacturing a nanofiber composite sheet, the method including: preparing a base sheet; surface-treating the base sheet; and forming a substrate layer having a nanofiber structure on the surface-treated base sheet.

The base sheet may include a polymer material.

The polymer material may be at least one selected from a group consisting of polypropylene (PP), polyethylene (PE) and polyethylene terephthalate (PET).

The surface-treating may be performed by irradiating energy onto the surface of the base sheet.

The surface-treating may be performed by at least one method selected from a group including a corona treatment, a plasma treatment and an electromagnetic wave irradiation treatment.

The forming of the substrate layer may be performed by an electrospinning process.

The method may further include, after the forming of the substrate layer, compressing the base sheet and the substrate layer.

According to an aspect of the present invention, there is provided a nanofiber composite sheet including: abase sheet having a hydrophilic group formed on a surface thereof; and a substrate layer having a nanofiber structure and formed on the surface of the base sheet, the base sheet having the hydrophilic group formed on the surface thereof.

The base sheet may include a polymer material.

The polymer material may be at least one selected from a group consisting of polypropylene (PP), polyethylene (PE) and polyethylene terephthalate (PET).

The hydrophilic group may be formed by irradiating energy onto the surface of the base sheet.

The hydrophilic group may be formed by at least one method selected from a group including a corona treatment, a plasma treatment and an electromagnetic wave irradiation treatment.

The substrate layer may be formed by an electrospinning process.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a perspective view schematically showing a nanofiber composite sheet according to an embodiment of the present invention;

FIG. 2 is a cross-sectional view taken along line A-A′ of FIG. 1;

FIG. 3 is a process diagram illustrating a method of manufacturing the nanofiber composite sheet according to the embodiment of the present invention;

FIG. 4 is a flow chart illustrating the method of manufacturing the nanofiber composite sheet according to the embodiment of the present invention;

FIG. 5A is a scanning electron microscope (SEM) photograph showing a micro structure of a base sheet before performing a surface-treatment thereon;

FIG. 5B is a scanning electron microscope (SEM) photograph showing a micro structure of a base sheet after performing a surface-treatment thereon;

FIG. 6 is a view schematically showing an electrospinning device used in manufacturing the nanofiber composite sheet according to the embodiment of the present invention;

FIG. 7 is a photograph showing adhesion test results of the nanofiber composite sheets between Inventive Example and Comparative Example; and

FIGS. 8A through 8C are photographs showing adhesion test results of the other nano fiber composite sheets between Inventive Example and Comparative Example.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. In the drawings, the shapes and dimensions of elements may be exaggerated for clarity, and the same reference numerals will be used throughout to designate the same or like elements.

An embodiment of the present invention provides a nanofiber composite sheet 10 including: a surface-treated base sheet 1; and a substrate layer 2 having a nanofiber structure and formed on the base sheet.

Hereinafter, the nanofiber composite sheet 10 and a method of manufacturing the same will be described in detail with reference to the accompanying drawings.

FIG. 1 is a perspective view schematically showing the nanofiber composite sheet according to the embodiment of the present invention.

FIG. 2 is a cross-sectional view taken along line A-A′ of FIG. 1.

FIG. 3 is a process diagram illustrating a method of manufacturing the nanofiber composite sheet according to the embodiment of the present invention.

FIG. 4 is a flow chart illustrating the method of manufacturing the nanofiber composite sheet according to the embodiment of the present invention.

The method of manufacturing the nanofiber composite sheet according to the embodiment of the present invention may include: preparing the base sheet (S1); surface-treating the base sheet (S2); and forming the substrate layer having the nanofiber structure on the surface-treated base sheet (S3), and may further include: after forming of the substrate layer, compressing the base sheet and the substrate layer (S4).

Hereinafter, respective processes in the method will be described in detail.

(a) Preparing Base Sheet (S1)

As the base sheet 1, an organic material is generally used, and specifically, a polymer material is mainly used, but the present invention is not specifically limited thereto. Any polymer material such as polyvinyl alcohol (PVA), polyvinylidene fluoride (PVDF), polyethylene oxide, polyurethane (PU), polypropylene (PP), polyethylene (PE) and polyethylene terephthalate (PET) maybe used as the base sheet.

Specifically, polypropylene (PP), polyethylene (PE) and polyethylene terephthalate (PET) having relatively high crystallinity, low polarity, and high cohesion may be more appropriate for the base sheet.

(b) Surface-treating Base Sheet (S2)

Then, energy is irradiated onto the prepared base sheet 1 to surface-treat the base sheet 1. The surface-treatment is performed for improving adhesion between the base sheet 1 and the nanofiber substrate layer 2, wherein a chemical bond on the surface of the base sheet 1 material is broken to generate a hydrophilic group on the surface of the base sheet 1.

The surface-treatment may be performed by applying energy to the base sheet 1, and the energy required for breaking the chemical bond of the base sheet may be varied according to the material of the base sheet.

The forming of the hydrophilic group on the surface of the base sheet 1 may be performed by at least one method selected from a group including a corona treatment, a plasma treatment and an electromagnetic wave irradiation treatment, and here, an appropriate energy source 11 may be selected according to a type of bond in the material constituting the base sheet 1 to irradiate the selected energy source.

The electromagnetic wave may correspond to a wave from within the entire region of the electromagnetic spectrum such as ultraviolet rays, visible rays, infrared rays, micro waves, and the like.

FIG. 5A is a scanning electron microscope (SEM) photograph showing the surface of the base sheet before performing a surface-treatment thereon; and FIG. 5B is a scanning electron microscope (SEM) photograph showing the surface of the base sheet after performing a surface-treatment thereon.

The base sheet shown in FIGS. 5A and 5B was formed of polyester, and the base sheet shown in FIG. 5B was surface-treated by irradiating ultraviolet rays thereon. In addition, as shown in FIG. 5B, it can be appreciated that there was no physical modification of the surface of the base sheet due to the ultraviolet ray irradiation, and although not shown in the drawings, it can be appreciated that a carboxyl group (—COOH) in which the hydrophilic group was formed was formed on the surface of the base sheet by a FT-IR spectrum test.

That is, only a chemical change occurred on the surface of the base sheet due to the surface-treatment.

(c) Forming Substrate Layer having Nano Fiber Structure (S3)

The substrate layer 2 having the nanofiber structure is formed on the surface of the surface-treated base sheet 1.

The surface of the base sheet 1 has the hydrophilic group formed by the surface-treatment, such that in the case in which the nanofiber is formed on the base sheet, adhesion between the nanofiber and the base sheet is improved. The forming of the substrate layer 2 having the nanofiber structure may include all methods capable of obtaining a form of the nanofiber, and examples of the forming thereof may include an electrospinning method, a meltblown method, or the like. The electrospinning method may include both of generally known solvent electrospinning method and melting electrospinning method.

FIG. 6 is a view schematically showing an electrospinning device.

The electrospinning method is a method of momentarily spinning a solution having relatively low viscosity as a fiber form by electrostatic force.

The molten nano fiber material passes through a high power supply part 22 to be spun on the base sheet 1 on a current collector 21 in the nanofiber form. The current collector 21 may be connected to a motor 23.

The electrospinning method is characterized by using a material having a microscale diameter to be capable of manufacturing a fiber having a nanometer unit.

In the case of using the electrospinning method, a microfiber may be manufactured, and in the case of collecting the microfiber, a web may be obtained.

As the material of the nanofiber forming the substrate layer 2, all of an organic material, an inorganic material, and a metal material may be used, and the present invention is not particularly limited in selecting the material.

(d) Compressing Base Sheet and Substrate Layer (S4)

After the forming of the substrate layer 2, the base sheet 1 and the substrate layer may be compressed to obtain the nanofiber composite sheet.

The compression method is not specifically limited as long as the base sheet and the substrate layer may be compressed, and an example of the compression method may include thermal compression using a calendering method.

Experimental Example 1

FIG. 7 is a photograph showing adhesion test results of the base sheet manufactured before and after performing the surface-treatment and the electrospun substrate layer having the nanofiber structure. A tape test method was used in a manner in which a tape was attached to the manufactured sample and detached therefrom by the same force.

A nonwoven fabric was used as the base sheet, and the surface-treatment was performed by irradiating ultraviolet ray.

The left side of FIG. 7 showed a tape test result obtained by using the base sheet which was not surface-treated, and the right side thereof showed a tape test result obtained by using the base sheet which was surface-treated. It can be appreciated that in the case of using the surface-untreated base sheet, the nanofiber was significantly detached by the tape, and in the case of using the surface-treated base sheet, even when the tape test was performed, it can be appreciated that the nanofiber was not detached.

That is, it could be confirmed that adhesion between the base sheet and the nanofiber was significantly improved due to the surface-treatment.

Experimental Example 2

FIGS. 8A through 8C are photographs showing adhesion test results of the other nano fiber composite sheets between Inventive Example and Comparative Example.

FIG. 8A, FIG. 8B, and FIG. 8C showed the adhesion test results of the nanofiber composite sheets of Comparative

Example 1, Comparative Example 2, and Inventive Example 1, respectively.

Similar to Experimental Example 1, the adhesion test was performed by the tape test.

In the nanofiber composite sheet of Comparative Example 1, the base sheet and the substrate layer having the nanofiber structure were formed, respectively, and then an adhesive spray was applied to the base sheet to adhere the base sheet and the substrate layer to each other.

In the nanofiber composite sheet of Comparative Example 2, the base sheet and the substrate layer having the nanofiber structure were formed, respectively, a plasma treatment was performed on the substrate layer having the nanofiber structure, and the base sheet and the substrate layer were adhered to each other.

In the nanofiber composite sheet of Inventive Example 1, ultraviolet rays were directly irradiated onto the surface of the base sheet, the nanofiber was formed on the base sheet by the electrospinning method, and the base sheet and the substrate layer were adhered to each other.

When considering the tape test result of the nanofiber composite sheet of Comparative Example 1 shown in FIG. 8A, it could be appreciated that the substrate layer was significantly detached by the tape, and when considering the tape test result of the nanofiber composite sheet of Comparative Example 2 shown in FIG. 8B, it could be appreciated that the substrate layer was completely detached by the tape, such that adhesion was extremely weak.

Meanwhile, when considering the tape test result of the nanofiber composite sheet of Inventive Example 1 shown in FIG. 8C, it can be appreciated that the substrate layer was not adhered to the tape, such that the adhesion between the base sheet and the substrate layer was significantly excellent.

Experimental Example 3

The following Table 1 is a result obtained by testing permeability of the nanofiber composite sheets of Comparative Example 1, Comparative Example 2, and Inventive Example 1, manufactured by the same method as that of Experimental Example 2, respectively.

TABLE 1 Comparative Comparative Inventive Example 1 Example 2 Example 1 Differential 68 32 32 permeability pressure (kPa)

It can be appreciated from Table 1 above that in the case of Comparative Example 1, permeability was not secured due to the adhesive agent, while in the case of Comparative Example 2 and Inventive Example 1, permeability was secured.

As set forth above, according to the embodiment of the present invention, the nanofiber composite sheet having permeability and excellent adhesion between the nanofiber substrate layer and the base sheet, and the method of manufacturing the same, may be provided.

While the present invention has been shown and described in connection with the embodiments, it will be apparent to those skilled in the art that modifications and variations can be made without departing from the spirit and scope of the invention as defined by the appended claims. 

What is claimed is:
 1. A method of manufacturing a nanofiber composite sheet, the method comprising: preparing a base sheet; surface-treating the base sheet; and forming a substrate layer having a nanofiber structure on the surface-treated base sheet.
 2. The method of claim 1, wherein the base sheet includes a polymer material.
 3. The method of claim 2, wherein the polymer material is at least one selected from a group consisting of polypropylene (PP), polyethylene (PE) and polyethylene terephthalate (PET).
 4. The method of claim 1, wherein the surface-treating is performed by irradiating energy onto the surface of the base sheet.
 5. The method of claim 1, wherein the surface-treating is performed by at least one method selected from a group including a corona treatment, a plasma treatment and an electromagnetic wave irradiation treatment.
 6. The method of claim 1, wherein the forming of the substrate layer is performed by an electrospinning process.
 7. The method of claim 1, further comprising, after the forming of the substrate layer, compressing the base sheet and the substrate layer.
 8. A nanofiber composite sheet comprising: a base sheet having a hydrophilic group formed on a surface thereof ; and a substrate layer having a nanofiber structure and formed on the surface of the base sheet, the base sheet having the hydrophilic group formed on the surface thereof.
 9. The nanofiber composite sheet of claim 8, wherein the base sheet includes a polymer material.
 10. The nanofiber composite sheet of claim 9, wherein the polymer material is at least one selected from a group consisting of polypropylene (PP), polyethylene (PE) and polyethylene terephthalate (PET).
 11. The nanofiber composite sheet of claim 8, wherein the hydrophilic group is formed by irradiating energy onto the surface of the base sheet.
 12. The nanofiber composite sheet of claim 8, wherein the hydrophilic group is formed by at least one method selected from a group including a corona treatment, a plasma treatment and an electromagnetic wave irradiation treatment.
 13. The nanofiber composite sheet of claim 8, wherein the substrate layer is formed by an electrospinning process. 